Rheem GNU75-125

75 Gallon Natural Gas Ultra Low Nox Commercial Water Heater 125000 Max BTU Input

Item # BCI2143234   |   Model # GNU75-125   |  Universal Heavy Duty Collection

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Universal Heavy Duty Collection Commercial Natural Gas Ultra Low Nox Water Heater with 75 Gallon Tank

Need a ultra low nitrous oxide solution? Rated for less than 14 ng/J this unit features an ultra low NOx burner. Part of the Universal Heavy Duty collection of water heaters, this unit is an excellent choice for commercial retrofits. Its compact size and multiple water connections simplify installations. Need installation flexibility? This water heater has water inlets and outlets on top, front, and rear.

Minimize Down Time

The stainless steel burner assembly slides out like a drawer for quick inspection and maintenance. Factory installed brass drain valve features full-port, full flow which allows faster draining and servicing. Multiple magnesium anode rods ensure corrosion resistance for longer tank life.

Save money

The Direct Spark-to-Pilot ignition is designed to save energy and only ignites the pilot when there is a call for heat.

Patented Technology

Patented multi-flue design using a proprietary steel formulation, combined with two coats of porcelain enamel, and the results equal a superior heat exchanger.

System Sentinel

Rheem's exclusive diagnostic system. It watches over the water heater and verifies system operation sequence by sequence via LED lights.

Ultra Low NOx Burner

Need less than 14 ng/J performance? This burner delivers. The power assist burner design incorporates stainless steel multi-port burner tubes for long term ultra low NOx performance. A sight glass allows for burner observation. The entire design is removable and is highly resistant to the effects of negative air pressure common in modern commercial buildings.


  • Tank Capacity: 75 Gallons
  • Thermal Efficiency: 80%
  • Performance:
    • First Hour Rating: 174 gallons
    • Recovery in GPH at 60 degree rise: 202
    • Recovery in GPH at 70 degree rise: 173
    • Recovery in GPH at 80 degree rise: 152
    • Recovery in GPH at 90 degree rise: 135
    • Recovery in GPH at 100 degree rise: 121
  • Max BTU Input: 125000
  • Warranty: 3 Year Limited Tank
  • Altitude Certification: 2000 ft. above sea level

Rheem has been manufacturing water heaters since the 1930's, with coast to coast distribution by 1936. Their product offerings cover commercial and residential heating, cooling, solar water heating systems, conventional storage-style water heaters, tankless water heaters, replacement parts and accessories. Rheem's manufacturing facilities are ISO 9001 certified, with four facilities in the United States. Choose an industry leader that is respected for reliability. Choose Rheem.

Additional Rheem Links

This Rheem item can also be referenced by the following color/finish specific model #:

  • Rheem GNU75-125

*Discontinued model or finish

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Installation Resource Center

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